THE INTESTINES. 



525 



fibres, which are reduced to a threefold or even only a twofold stratum ; 

 in the rectum, the layers are again of equal thickness, and, taken to- 

 gether, measure about 0-022, at the anus even 0-088 of a line and 

 more. 



The glandular organs of the large intestine are LieberTcuhn' s glands 

 and solitary follicles ; the former, also termed glands of the large intes- 

 tine, are distributed over its whole surface from the ileo-csecal valve to 

 the anus and in the processus vermicular is. They are closely set, and 

 have exactly the same structure as those of the small intestine, only, in 

 accordance with the greater thickness of the mucous membrane, they 



Fig. 217. 



are longer and broader (J--J of a line long, yVVo of a line broad). 

 Here also I have found, in man and in animals, in the fresh state, no 

 formed contents besides a beautiful cylinder epithelium ; so that we have 

 no reason to suppose that the secretion is at all different from that in 

 the glands of the small intestine, especially as the mucous membrane 

 has, like that of the latter, an alkaline reaction, and, so far as my own 

 experiments go, is equally devoid of digestive action. 



The solitary follicles are arranged close together in the processus ver- 

 micularis, are very frequent in the ccecum and rectum, and are also 

 usually more abundant in the colon 

 than in the small intestine. They 

 are distinguished from those of the 

 latter locality by their larger size 

 (f-l-lj lines) and by the circum- 

 stance that upon each of the little 

 prominences of the mucous mem- 

 brane to which the follicles give rise, 

 there is a small pit-like, elongated 

 or rounded aperture, of 1-9-1-12 of 

 a line, which leads to a little depres- 

 sion of the mucous membrane above 

 the follicles. These pits, which are 

 totally absent in the normal follicles 



of the small intestine, led Bohm formerly to regard the follicles as csecal 

 glands provided with apertures : this, however, is incorrect, for at the 

 bottom of this depression lies, as Brucke has also remarked, a closed, 

 somewhat flattened follicle of exactly the same structure, even to the 

 internal vessels, as those of the small intestine. 



The bloodvessels of the glands and follicles of the large intestine pre- 

 sent the same relations as in the small. Every Lieberklihnian aperture 

 is encircled by a ring of vessels of 0-006-0-01 of a line, which is some- 



FIG. 217. Solitary follicle from the colon of a Child, magnified 45 diameters: a, Lieber- 

 ktihn's glands ; b, muscular layer of the mucous membrane ; c, submucous tissue ; rf, trans- 

 verse muscles ; e, serous membrane ; /, depression of the mucous membrane above the 

 follicle, a. 



